The present disclose generally relates to an air intake control device for a motor vehicle. More particularly, the present disclosure relates to a high flow dual bore throttle body for an internal combustion engine.
Internal combustion engines require a precise mixture of air and gasoline in order to run properly. Throttle bodies are designed to regulate and adjustably control airflow into the cylinders of the engine. Electronic-controlled throttle bodies are well known for throttle control. In order to control airflow that reaches the cylinders, the throttle body generally includes a rotatably disposed throttle valve or throttle plate. The throttle plate is attached to a throttle shaft and configured such that the throttle plate is located within an intake passage or throttle bore, or proximal to an end of the throttle bore. With rotation of the shaft, the throttle plate is able to selectively regulate the area of the throttle bore, thereby selectively obstructing airflow through the throttle bore. More specifically, the throttle plate is able to rotate with respect to the bore in order to adjust the cross-sectional area of the bore that is not obstructed by the throttle plate (the “effective area”), thus controlling airflow that is permitted to flow through the throttle bore.
In order to control the effective area of the intake passage, the throttle plate is sized and shaped approximately the same as the cross-section of the bore to be able to completely or substantially obstruct the bore when the throttle plate is substantially perpendicular to the airflow (the “closed position”). Additionally, the throttle plate has a minimal thickness in order to not substantially obstruct airflow through the throttle bore when the plate is angled such that the throttle plate face is not substantially perpendicular to the airflow (the “open position”).
During operation, when the engine is idling, the throttle plate is in the closed position because very little air is needed to mix with the small amount of fuel being injected into the engine. For throttle bodies having no bypass, the throttle plate generally has an initial set angle for idle speed control. Conversely, the throttle plate is in a variety of open positions at operating speeds higher than idle because more air is needed to mix with the increased amount of fuel being provided to the engine.
As the power output of small displacement engines continues to increase, a key design parameter is the flow rate of intake air to the engine. The quantity of intake air to the engine is generally limited by the size of the throttle body. To increase airflow, a large bore with a large single throttle plate can be implemented. However, due to the small displacement of the engine, idle speed control becomes a concern. This is because even a small throttle angle produces a large flow rate of intake air when a large single throttle plate is used.
Accordingly, there is need for an improved throttle body for a small displacement engine which would allow the engine to have a more stable function at lower engine speeds eliminating the idle stability concerns, but would also provide an increased effective area allowing for increased airflow and the ability to increase power out of the engine.